1. Field of Invention
The present invention relates to data transmission over a wireless network, particularly to a system and method and program-storing media for continuous downloading of large-size content data over a wireless network by managing a temporary file of plural contents and organizing content data into multiple files.
2. Description of the Related Technology
Recently, through the rapid development of the Internet, lots of people have access to a variety of content.
The term content refers to various kinds of information, such as text, music, games and movies and also executable programs for reproducing the above-mentioned content on a user terminal, provided over the Internet.
The content used to be downloaded through the landline Internet and to be played on a desktop PC or a notebook computer. However, with the widespread use of cellular phones, PDAs (Personal Digital Assistants), and the like, the content access by mobile terminals is rapidly increasing.
Currently, it is possible to provide several mega-bytes to several gigabytes of content due to the technological development of multimedia data transmission over the landline Internet and improved performance of desktop PCs or notebook computers, but in providing content to mobile terminals, only small-size content can be sent to mobile terminals due to the limited memory capacity, lagging performance of mobile terminals and instability of wireless networks.
In transmitting content over a wireless network, the content transmission process may be suspended when the mobile terminal leaves the communication coverage or is turned off.
When a user requests content download, which was previously suspended, it is common that a continuous download service to download the remaining part of the file is not available because the size of the content was small.
Although continuous download services are available today, these services are still very much limited because the probability of disconnection increases in proportion to the increase in content size.
Generally, in downloading the content through a wireless network, the mobile terminal stores the data being downloaded in the form of a temporary file and converts it into an executable file after the download is finished.
Since a conventional mobile terminal can accommodate only one temporary file due to its limited memory capacity, it is possible for the mobile terminal to continue the download by using the stored temporary file only when the retransmission request for the suspended content is made right after the suspension occurred. However, the mobile terminal must delete the old temporary file and generate a new temporary file if the user requests to download another content.
Thus, if there is no download request for the suspended content successively, the partially downloaded content must be downloaded from the beginning.
Generally, the charge for the content is made only after finishing the transmission of the content. For example, in downloading a 100-megabyte content file, a wireless communication service provider (hereinafter, carrier) can charge for the content download only when the whole content is downloaded. If 30 megabytes of the 100-megabyte content were downloaded at first and then the remaining 70 megabytes were downloaded by using the continuous download service, the carrier could not charge for these continuous downloads because the first 30 megabytes and the last 70 megabytes were regarded as incomplete downloads of the content.
Also, since the content is usually organized into one file, if there is a patch file for the content, the whole content to which the patch file is applied (hereinafter, patched content) must be downloaded again. However, if the user requests a download of the suspended content and there is a patch file for the requested content, the remaining content will be download first and then the patched content will be download again, making the user download almost the same content twice.